JP2012229708A - Planetary gear train, rotary drive device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planetary gear train that absorbs errors of coaxiality and linearity between a rotating shaft and an output shaft of a body to be rotated, suppresses a variation of a rotation speed more than before, can transmits an accurate rotation drive force, is favorable in maintainability, and low in cost.SOLUTION: The output shaft 119 is arranged at a joint which transmits the rotation drive force to a drum rotating shaft 151 of a photosensitive drum 40. A carrier 118 at a second stage having the rotating shaft 119 is floatingly supported. Furthermore, the coaxiality between the drum drive shaft 151 and a drive motor shaft 141 of a drive motor 140 is secured by using a rigid bracket 130 which connects the planetary gear reduction mechanism 110 and the drive motor 140. Then, the side of the output shaft 119 of a resin-made fixed inner-tooth gear 111 is not regulated in positioning nor fixed.

Description

  The present invention relates to a planetary gear mechanism that shifts and transmits rotation of a drive source to a rotated body, a rotational drive device including the planetary gear mechanism, and an image forming apparatus including the planetary gear mechanism.

  2. Description of the Related Art Conventionally, various speed change mechanisms are known as speed change mechanisms that change and transmit the rotational drive force of a rotational drive source to a rotated body. For example, Patent Document 1 describes a planetary gear reduction mechanism configured as follows. An output shaft formed integrally with the final stage carrier is pivotally supported by a lid portion which is an end plate on the output shaft side of the planetary gear reduction mechanism. The output shaft and the rotating shaft of the rotated body are engaged to transmit a rotational driving force, and the output shaft and the rotated body are detachable.

  Patent Document 2 describes a traction type (friction transmission type) planetary speed reduction mechanism configured as follows. In a rotational drive unit of a photosensitive drum using a traction type planetary speed reduction mechanism, the photosensitive drum shaft is inserted into the planetary speed reduction mechanism while being rotatably supported by a ball bearing, and is integrated with the output shaft of the planetary speed reduction mechanism. It is configured. By integrally configuring the photosensitive drum shaft and the output shaft of the planetary reduction mechanism, it is possible to eliminate errors in the coaxiality and straightness between the photosensitive drum shaft, which is the rotating shaft of the rotated body, and the output shaft of the carrier. . That is, it is possible to eliminate the cause of fluctuations in the rotational speed of the rotated body when the rotating shaft of the rotated body and the output shaft of the planetary reduction mechanism are provided separately.

  In recent years, there is a demand for a transmission mechanism that shifts and transmits the rotational driving force of a rotational driving source to a body to be rotated, and that the rotational speed fluctuation is suppressed more than before and the rotational driving force is transmitted with high accuracy. For example, in an image forming apparatus, due to the increasing demand for higher image quality and higher speed of the image forming apparatus, the rotational speed of the speed change mechanism to be used is suppressed more accurately than in the past, and high-precision rotation drive that does not cause a binding phenomenon or the like. Power transmission is required. On the other hand, there are high demands for cost reduction, mass productivity improvement and maintenance improvement.

  As a factor of the rotational speed fluctuation of the rotated body to which the rotational driving force of the rotational drive source is transmitted via the speed change mechanism, a factor related to the positional error between the rotation axis of the rotated body and the output shaft of the speed change mechanism has a great influence. To do. For example, eccentricity of the rotating shaft of the rotated body, fastening accuracy by a joint mechanism that connects the rotating shaft of the rotated body and the output shaft of the speed change mechanism, and coaxiality or straightness between the rotating shaft of the rotated body and the output shaft. Sexual errors are cited as the main factor. Further, in the planetary mechanism, a concentricity error of a plurality of planetary gears and planetary rollers arranged on the carrier in the planetary mechanism is also cited as a main factor.

  However, only the configuration of the planetary gear speed reduction mechanism described in Patent Document 1 reduces the eccentricity of the rotating shaft of the rotated body or the joint mechanism that connects the rotating shaft of the rotated body and the output shaft of the speed reducing mechanism. It is difficult to increase the fastening accuracy. It is also difficult to suppress errors in coaxiality and straightness between the rotating shaft and output shaft of the rotated body and concentricity errors in a plurality of planetary gears arranged on the carrier.

  Further, in the configuration of the traction type planetary speed reduction mechanism described in Patent Document 2, it is necessary to increase the accuracy of each part and the assembly accuracy to the micron order, thereby increasing the manufacturing cost. At the same time, it is not suitable for mass production. In addition, a method of first integrating and assembling a photosensitive drum shaft, which is a rotating shaft of a rotated body, and a drive system into a main body of the apparatus to be used is also a good method in consideration of improving maintenance. It's hard to say.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide the following planetary gear mechanism, a rotational drive device including the planetary gear mechanism, and an image forming apparatus including these. It is. Absorbs errors in the coaxiality and straightness between the rotating shaft and output shaft of the rotating body, suppresses rotational speed fluctuations compared to the previous model, and transmits highly accurate rotational driving force. It is a planetary gear mechanism.

In order to achieve the above object, an invention of a planetary gear mechanism according to claim 1 is directed to an output shaft having a joint portion for transmitting a rotational driving force to a driving shaft of a rotated body, a fixed internal gear, A planetary gear mechanism comprising a plurality of planetary gears meshed with a fixed internal gear and a carrier having the output shaft, and mounted on an apparatus body including the rotated body in combination with a rotation drive source. The mechanism and the rotational drive source are fixedly attached to the side plate of the apparatus body via a rigid bracket, and the bracket ensures the coaxiality of the drive shaft of the rotated body and the drive shaft of the rotational drive source, and the output shaft The fixed internal gear is a resin molded product, and the output shaft side of the fixed internal gear is neither positioned nor fixed, and the fixed internal gear Part of when rotating It has a structure in which deformed by forces resulting from the eccentric error of the drive shaft of the rotary member and the output shaft is characterized in.
According to a second aspect of the present invention, in the planetary gear mechanism of the first aspect, in order to obtain the deformability of the fixed internal gear, a thin groove portion is formed in a part of the fixed internal gear to form a planetary gear. It is formed in the part which a gear does not mesh.
According to a third aspect of the present invention, in the planetary gear mechanism according to the first aspect, in order to obtain the deformability of the fixed internal gear, a continuous thin portion is formed in a part of the fixed internal gear. It is characterized by this.
According to a fourth aspect of the present invention, in the planetary gear mechanism according to the second or third aspect, the planetary gear of the carrier having an output shaft is used to obtain the deformability of the fixed internal gear of the two-speed transmission mechanism or higher. In the vicinity, a groove portion or a thin portion is provided.
According to a fifth aspect of the present invention, in the planetary gear mechanism according to any one of the second to fourth aspects, the vibration-absorbing material made of an elastic and deformable elastomer is used as the groove portion or the thin-wall portion. It is characterized by being applied to the outer periphery of the fixed internal gear provided.
According to a sixth aspect of the present invention, in the planetary gear mechanism according to the fifth aspect of the present invention, the vibration absorbing material is fixed so as to bury at least the thin portion for deformation provided in the fixed internal gear. It is characterized by.
According to a seventh aspect of the present invention, in the planetary gear mechanism according to any one of the first to sixth aspects, the carrier having the output shaft is fixed to the plurality of planetary gears included in the carrier. It is performed by meshing with an internal gear.
According to an eighth aspect of the present invention, there is provided a rotary drive device for rotationally driving a rotated body, wherein the rotational drive force of a rotational drive source is shifted and transmitted to the rotated body. The planetary gear mechanism described in any one of 1 to 7 is provided.
According to a ninth aspect of the present invention, in the image forming apparatus having a plurality of rotating bodies, at least one of the plurality of rotating bodies is driven to rotate. The planetary gear mechanism according to any one of claims 1 to 7 or the rotary drive device according to claim 8 is used.
In the present invention, since the output shaft for transmitting the rotational driving force to the drive shaft of the rotated body has a joint portion, the rotational shaft of the rotated body and the drive system can be separated and separated. it can. Since separation is possible in this way, maintenance can be improved as compared with a method in which a rotating shaft and a drive system of a rotating body are first integrated and assembled into a device main body to be used.
Further, by floatingly supporting the carrier having the output shaft, it is possible to perform high-precision rotation while suppressing fluctuations in the rotational speed of the drive shaft of the rotated body, compared to the case where the carrier is supported by a bearing. This is due to the following reason. In general, when the output shaft of the planetary gear mechanism is rotationally supported, a fitting tolerance play is defined for each support method, and the radial play amount of the output shaft is regulated. For example, in a planetary gear mechanism used in an image forming apparatus or the like, the fitting tolerance play in the case of a ball bearing is about 1 μm to 10 μm, and the fit tolerance play in the case of a sliding bearing is about 10 μm to 50 μm. Regulate the amount. On the other hand, in the case of floating support, a backlash of about 100 to 150 μm, which is a rough tolerance of more than that, is given. By this play, the carrier having the output shaft can be set to an amount that allows a smooth and trouble-free positional shift. That is, the eccentricity of the rotating shaft of the rotated body, the fastening accuracy by the joint mechanism connecting the rotating shaft of the rotated body and the output shaft of the planetary gear mechanism, the coaxiality and straightness of the rotating shaft and the output shaft of the rotated body More tolerance of gender is acceptable than when supported by bearings. Also, even if the planetary gear has variations in accuracy (variations in rotational eccentricity and tooth shape accuracy) and the meshing is shallow with respect to the shallow meshing, the meshing resistance of the gear does not occur due to the degree of freedom of the floating support part. . Since resistance does not occur in this way, the output shaft is rotated with a degree of freedom. As described above, it can tolerate more errors in coaxiality and straightness than when supported by a bearing, and can rotate with a degree of freedom, enabling high-precision rotation with reduced rotational speed fluctuations. It is.
In addition, by floatingly supporting a carrier having an output shaft, it is possible to suppress rotational speed fluctuations without increasing the accuracy and assembly accuracy of each component with an increase in manufacturing cost like the planetary reduction mechanism described in Patent Document 2. And an increase in manufacturing cost can be suppressed.
In addition, a rigid bracket for attaching the planetary gear mechanism and the rotational drive source, and a fixed internal gear that is a resin molded product while ensuring the coaxiality of the drive shaft of the driven body and the drive shaft of the rotational drive source The output shaft side is neither positioned nor fixed. Since the resin-made fixed internal gear is fixed in this manner, a part of the fixed internal gear is deformed by a force generated from an eccentric error between the drive shaft and the output shaft of the rotated body at the time of rotational drive. Due to this deformation, it is possible to reduce fluctuations in rotational torque caused by the coupling between the drive shaft of the rotated body and the output shaft during rotational driving. In addition, the deformation amount of this deformation is added to the amount of the coaxiality or straightness error between the rotating shaft of the rotating body and the output shaft, which can be allowed by a configuration in which the carrier having the output shaft is only floated and supported. Can do. As a result, it is possible to absorb more fluctuations in the rotational speed of the drive shaft of the driven body than in the configuration in which the carrier having the output shaft is only supported in a floating manner.

The present invention can improve maintainability as compared with a method of incorporating a rotating body of a rotating body and a drive system that are first integrated and assembled into an apparatus main body. Further, it is possible to perform high-accuracy rotation in which the rotational speed fluctuation of the drive shaft of the rotated body is suppressed as compared with the case where it is supported by the bearing, and it is possible to suppress an increase in manufacturing cost. In addition, it is possible to absorb more fluctuations in the rotational speed of the drive shaft of the body to be rotated than in a configuration in which the carrier having the output shaft is only supported in a floating manner.
Therefore, it is possible to provide the following planetary gear mechanism, a rotational drive device including the planetary gear mechanism, and an image forming apparatus including these. Absorbs errors in the coaxiality and straightness between the rotating shaft and output shaft of the rotating body, suppresses rotational speed fluctuations compared to the previous model, and transmits highly accurate rotational driving force. It is a planetary gear mechanism.

1 is an explanatory diagram of an overall configuration of an image forming apparatus according to an embodiment. FIG. 3 is an explanatory diagram of a drive module according to the first embodiment. FIG. 3 is an explanatory diagram of joining of the photosensitive drum unit and the drive module according to the first exemplary embodiment and positioning of the drum drive shaft and the output shaft by a rigid bracket. Explanatory drawing of the drive module of Example 2. FIG. FIG. 5 is an explanatory diagram of another example of the groove portion of the second embodiment. Explanatory drawing of the drive module of Example 3. FIG. Explanatory drawing of the drive module of Example 4. FIG. FIG. 10 is an explanatory diagram of another example of the fourth embodiment. Explanatory drawing of the drive module of Example 5. FIG.

  The present invention is applied to an example of an embodiment in which the present invention is applied to a photosensitive drum rotation driving device of a color-compatible MFP (hereinafter, referred to as a multi-function machine) which is an electrophotographic image forming apparatus, and the drawings are used as examples. I will explain. FIG. 1 is an explanatory diagram of the overall configuration of the image forming apparatus according to the present embodiment. FIG. 2 is an explanatory diagram of the drive module of the first embodiment, and FIG. 3 is an explanatory diagram of the joining of the photosensitive drum unit and the drive module of the first embodiment and the positioning of the drum drive shaft and the output shaft by the rigid bracket. . 4 is an explanatory diagram of the drive module of the second embodiment, FIG. 5 is an explanatory diagram of another example of the groove portion of the second embodiment, FIG. 6 is an explanatory diagram of the drive module of the third embodiment, and FIG. FIG. 8 is an explanatory diagram of another example of the fourth embodiment. FIG. 9 is an explanatory diagram of a drive module according to the fifth embodiment.

  First, the configuration and operation of the multifunction machine of this embodiment will be described. As shown in FIG. 1, the copying machine mainly includes the following items. An image forming unit 100 that forms an image, a paper feed table 200 on which the image forming unit 100 is placed, a scanner 300 mounted on the image forming unit 100, and a document mounted on the scanner 300 This is an automatic transfer device (ADF) 400.

  The scanner 300 is placed on the contact glass 301 as the first traveling body 303 equipped with a document illumination light source or mirror and the second traveling body 304 equipped with a plurality of reflecting mirrors reciprocate. The scanned original is read and scanned. The scanning light sent out from the second traveling body 304 is condensed on the imaging surface of the reading sensor 306 installed behind the imaging lens 305 and then read as an image signal by the reading sensor 306.

  The image forming unit 100 is provided with photosensitive drums 40Y, 40M, 40C, and 40Bk corresponding to toners of yellow (Y), magenta (M), cyan (C), and black (Bk) as latent image carriers. It has been. Around the respective photosensitive drums 40, various units for performing an electrophotographic process such as a developing device 70, a charging device 85, and a photosensitive member cleaning device 86 are arranged, whereby an image forming unit 38 (Y, M, C, Bk) is arranged. ) Is formed. Each image forming unit 38 can be attached to and detached from the printer main body, so that consumable parts can be replaced at a time. Four image forming units 38 are provided in parallel to form the tandem image forming unit 20. Here, the configuration of each image forming unit 38 is different only in the color of the toner to be used, and the configuration and operation thereof are the same. Therefore, in the following description, symbols Y, M, C, and Bk are omitted as appropriate. I will explain.

  Each image forming unit 38 has a photosensitive drum unit 150. As shown in FIG. 2, the drum driving shaft 151 of the photosensitive drum 40 held by the drum holder 154 of the photosensitive drum unit 150 has a tip that protrudes to the outside from a shaft hole provided on one side of the drum holder 154. Is provided. In addition, when the image forming unit 38 is mounted, the external gear 153 formed at the tip of the drum drive shaft 151 meshes with the internal gear of the output shaft 119 of the drive module 105, which is a rotary drive device, which will be described later in detail. Parts. The drive module 105 includes a planetary gear reduction mechanism 110 and a drive motor 140. The photosensitive drum 40 is rotationally driven by a drive motor 140 provided in the drive module 105 by meshing the external gear 153 of the drum drive shaft 151 with the internal gear of the output shaft 119 of the drive module 105. It will be.

  In the developing device 70 of each image forming unit 38, the developer containing the four color toners is used. In the developing device 70, a developing roller 71 that is a developer carrying member carries and conveys the developer, and develops a latent image on the photoconductive drum 40 at a position facing the photoconductive drum 40.

  Above the tandem-type image forming unit 20, an exposure device 31 is provided that forms a latent image by exposing the photosensitive drum 40 with laser light or LED light based on image information.

  Further, an intermediate transfer belt 15 made of an endless belt member is disposed at a lower position facing the photosensitive drum 40 of the tandem type image forming unit 20. The intermediate transfer belt 15 is supported by a support roller 34, a support roller 35, and a secondary transfer backup roller 36. A primary transfer device 62 that transfers the toner images of the respective colors formed on the photosensitive drum 40 to the intermediate transfer belt 15 is disposed at a position adjacent to the photosensitive drum 40 via the intermediate transfer belt 15.

  Below the intermediate transfer belt 15, a secondary transfer device 19 that collectively transfers a toner image formed on the surface of the intermediate transfer belt 15 to the sheet P conveyed from the paper feed cassette 44 of the paper feed table 200. Is arranged. The secondary transfer device 19 includes a secondary transfer roller 23 and a contact / separation mechanism (not shown) that supports the secondary transfer roller 23 so as to be able to contact and separate from the intermediate transfer belt 15. The secondary transfer device 19 presses the secondary transfer roller 23 against the secondary transfer backup roller 36 via the intermediate transfer belt 15 to transfer the toner image on the intermediate transfer belt 15 onto the sheet P.

  An intermediate transfer belt cleaning unit 90 is provided to remove toner remaining on the surface of the intermediate transfer belt 15. The intermediate transfer belt cleaning unit 37 causes a cleaning blade made of, for example, a fur brush or urethane rubber to contact the intermediate transfer belt 15 and scrapes off secondary transfer residual toner attached to the intermediate transfer belt 15.

  A fixing device 60 is provided adjacent to the secondary transfer device 19, and the fixing device 60 fixes an image on the sheet P. The fixing device 60 mainly includes a heating roller 66 in which a heater as a heat source is incorporated, and a pressure roller 67 pressed against the heating roller 66.

  A reversing device 28 for reversing the sheet P is disposed below the secondary transfer device 19 and the fixing device 60. The reversing device 28 reverses the sheet P so as to record images on both sides of the sheet P.

  Next, the operation of the image forming apparatus having the above configuration will be described. The original document is set on the document table 30 of the automatic document feeder 400 shown in FIG. 1, or the automatic document feeder 400 is opened to set the document on the contact glass 301 of the scanner 300, and the automatic document feeder 400 is closed. . When a start switch (not shown) on the operation panel is pressed in this state, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 301, and then the first traveling body. 303 and the second traveling body 304 are caused to travel. Further, when an original is set on the contact glass 301, the scanner 300 is immediately driven to cause the first traveling body 303 and the second traveling body 304 to travel. The first traveling body 303 emits light from the light source and receives reflected light from the document surface. The reflected light is reflected toward the second traveling body 304, the reflected light is further reflected by the mirror of the second traveling body 304, enters the reading sensor 306 through the imaging lens 305, and the reading sensor 306 reads the content of the document. .

  Further, by pushing a start switch on the operation panel, a drive motor (not shown) is driven to rotate and drive one of the support roller 34, the support roller 35, and the secondary transfer backup roller 36, and the other two The support roller is driven to rotate. By rotating in this way, the intermediate transfer belt 15 is rotated. At the same time, the photosensitive drum 40 is uniformly charged by the charging device 85 in each image forming unit 38. Then, an electrostatic latent image is formed on each charged photosensitive drum 40 by irradiating writing light from a laser, LED, or the like from the exposure device 31 according to the content read by the scanner 300. Toner is supplied from the developing device 70 to the photosensitive drum 40 on which the electrostatic latent image is formed, and the electrostatic latent image is visualized. On each photosensitive drum 40, yellow (Y), magenta (M), A single color image of cyan (C) and black (Bk) is formed. A single color image is sequentially primary transferred by the primary transfer device 62 so as to overlap the intermediate transfer belt 15, and a composite color image is formed on the intermediate transfer belt 15. Residual toner is removed from the surface of the photosensitive drum 40 after the image transfer by the photosensitive member cleaning device 86, and the static electricity is removed by a static eliminator (not shown) to prepare for image formation again.

  By pressing the start switch on the operation panel, one of the paper feed rollers 42 of the paper feed table 200 is selected and rotated, and the sheet P is loaded from one of the paper feed cassettes 44 provided in the paper bank 43 in multiple stages. Pull out. The fed sheets P are separated one by one by the separation roller 45 and inserted into the paper feed path 46, transported by the transport roller pair 47 and guided to the paper feed path 48 in the image forming unit 100, and to the registration roller pair 49. Stop it by hitting it. Next, the registration roller pair 49 is rotated in synchronization with the composite color image on the intermediate transfer belt 15, and the sheet P is fed between the intermediate transfer belt 15 and the secondary transfer device 19 and transferred by the secondary transfer device 19. Then, the color image is transferred onto the sheet P.

  The sheet P carrying the unfixed toner image that has passed through the secondary transfer roller 23 is conveyed to the fixing device 60, and heat and pressure are applied by the fixing device 60 to fix the transferred image. The sheet P after image fixing is switched by the switching claw 55 and discharged by the discharge roller pair 56 and stacked on the paper discharge tray 57 or switched by the switching claw 55 and introduced into the reversing device 28. The sheet P introduced into the reversing device 28 is reversed and guided to the transfer position again, and an image is recorded on the back surface. Thereafter, the sheet P is discharged onto the discharge tray 57 by the discharge roller pair 56. At this time, residual toner remaining on the intermediate transfer belt 15 after the image transfer is removed by the intermediate transfer belt cleaning unit 90 to prepare for re-image formation by the tandem type image forming unit 20.

  Next, the drive module 105 including the planetary gear reduction mechanism 110, which is a characteristic part of the present embodiment, will be described with reference to the drawings. Here, the configuration of the driving module 105 corresponding to each image forming unit 38 is the same in the configuration and operation except that the color of the toner used in each corresponding image forming unit 38 is different. Therefore, in the following description, the symbols Y, M, C, and Bk are omitted as appropriate.

Example 1
The drive module 105 including the planetary gear speed reduction mechanism 110 according to the present embodiment will be described from Example 1 which is a first example. As shown in FIG. 2, the planetary gear reduction mechanism 110 and the drive motor 140 that is a driving source of the planetary gear reduction mechanism 110 are fixed to the motor side end plate 135 of the planetary gear reduction mechanism 110 and the motor plate 134 of the drive motor 140 by screws. Has been. Thus fixed, the planetary gear speed reduction mechanism 110 and the drive motor 140 drive form a module 105. The drive module 105 is connected to a drum drive shaft 151 that is separately supported and rotates to perform accurate rotation of the photosensitive drum 40. The drum drive shaft 151 and the output shaft 119 of the planetary gear speed reduction mechanism 110 are formed in such a divided configuration in consideration of ease of assembly to the apparatus main body and exchangeability during maintenance. Need to be coupled and rotated.

  The planetary gear speed reduction mechanism 110 mainly has the following. A fixed internal gear 111, which is a resin molded product having an internal gear 112 formed on a part of its inner peripheral surface, a first stage planetary gear 114, and a first stage carrier 115 are provided. doing. Further, it has a second stage sun gear 116 which is also a first stage output shaft connected to the first stage carrier 115, a second stage planetary gear 117, and a second stage carrier 118. . An output shaft 119 that is a second-stage output shaft connected to the second-stage carrier 118 is provided. The output shaft 119 is formed with an internal gear that meshes with the external gear 153 of the drum drive shaft 151. A motor-side end plate 135 is fixed to the inner peripheral surface end of the fixed internal gear 111 on the drive motor 140 side, and the output shaft-side end is fixed to the end of the fixed internal gear 111 on the output shaft 119 side. The plate 136 is screwed.

  The planetary gear speed reduction mechanism 110 is fixed by connecting the motor side end plate 135 to the rigid bracket 130 via the motor plate 134, and the side on which the output shaft side end plate 136 is fixed is a free end. Yes. In the planetary gear speed reduction mechanism 110, the second-stage carrier 118 having the output shaft 119 is floatingly supported without providing a bearing or the like.

  The drive motor 140 has a drive motor shaft 141 passing therethrough, and an external gear is formed on the drive motor shaft 141 on the planetary gear reduction mechanism 110 side. It functions as a gear 113. A hole through which the drive motor shaft 141 is passed is formed in the motor plate 134 of the drive motor 140. On the planetary gear reduction mechanism 110 side of the hole formed in the motor plate 134, a cylindrical positioning portion that fits into the hole formed in the motor-side end plate 135 is formed so as to protrude. By fitting the projecting portion with the hole of the motor-side end plate 135 and screwing, the planetary gear reduction mechanism 110 and the drive motor 140 are accurately positioned and screwed to form the drive module 105; Become.

  The drive module 105 assembled in this way is attached to the main body side attachment side plate 160 (hereinafter referred to as the side plate 160) of the apparatus main body via the rigid bracket 130.

  The drive module 105 of the present embodiment supports the fluctuation of the rotational speed of the drum drive shaft 151 due to the eccentricity of the drum drive shaft 151 and the output shaft 119 with the bearing by the floating support adopted in the planetary gear speed reduction mechanism 110. It can be suppressed more than if That is, the drive module 105 of the present embodiment can rotate the drum drive shaft 151 with higher precision than the case where the drive module 105 is supported by the bearing by the floating support adopted in the planetary gear reduction mechanism 110. In addition, in the drive module 105 of the present embodiment, the side on which the output shaft side end plate 136 of the planetary gear speed reduction mechanism 110 is fixed is used as a free end in order to achieve an effect more than the above-described floating support. By setting the free end in this way, a part of the fixed internal gear 111 with which the planetary gears mesh is deformed by about 50 μm at the maximum, and as a result, even if there is a deviation amount of about 150 to 200 μm as a whole, it can rotate freely It was made to rotate as a structure. As a result, the rotational speed fluctuation of the drum drive shaft 151 caused by the eccentricity of the drum drive shaft 151 and the output shaft 119 is more improved than the configuration in which the second-stage carrier 118 having the output shaft 119 is floated and supported. Can absorb much. Therefore, it is possible to transmit the rotational driving force with higher accuracy.

  For this purpose, position accuracy is secured at locations other than the joint portion between the drum drive shaft 151 and the output shaft 119 described above, and consideration is given so as not to generate higher-order vibration components caused by deformation. As shown in FIGS. 3A and 3B, in order to support the shaft center of the drive motor shaft 141 and the drum drive shaft 151 to be finally rotationally driven with high accuracy and high rigidity, an aluminum die cast or resin is used. A rigid bracket 130 made by molding or the like is interposed between the two. As shown in FIG. 3 (c), the rigid bracket 130 includes a disc-shaped base portion 131 in which a convex positioning portion 132 is formed, and a rotor holder 133 whose end is fixed to the base portion 131. Become. A bracket positioning hole 120 formed coaxially is formed in the convex positioning portion 132 and the base portion 131.

  Regarding the coaxial guarantee of the drive motor shaft 141 and the drum drive shaft 151 using the rigid bracket 130, the following configuration is provided. On the side plate 160 side, as shown in FIG. 3A, the convex positioning portion 132 of the rigid bracket 130 is fitted into a positioning hole formed in the side plate 160 and positioned on the apparatus main body. As shown in FIG. 3B, the outer ring of the ball bearing 155 that supports the rotation of the drum drive shaft 151 is fitted into the bracket positioning hole 120 by mounting the photosensitive drum unit 150 at the mounting position. Combined. By fitting in this way, the coaxiality of the rigid bracket 130 and the drum drive shaft 151 is ensured. On the drive module 105 side, the motor plate 134 fixed to the housing of the drive motor 140 and the holder 133 of the rigid bracket 130 are fitted so that the convex positioning portion 132 and the drive motor shaft 141 are coaxial. . By fitting in this way, the coaxiality of the rigid bracket 130 and the drive motor shaft 141 is ensured. On the other hand, the parallel security is determined by the accuracy of the screwing height of the motor holder 133 that rises from the side plate 160 side of the rigid bracket 130. In this way, as shown in FIG. 3D, the shaft center of the drive motor shaft 141 that is the sun gear of the planetary gear speed reduction mechanism 110 and the drum drive shaft 151 can be supported with high accuracy and high rigidity. it can.

  In addition, in the case of a deviation due to accumulation of errors that cannot be obtained even with the configuration using the rigid bracket 130, the rotational torque fluctuation is reduced by the partial deformation of the fixed internal gear 111, and the rotational speed fluctuation of the drum drive shaft 151 is reduced. Absorption will take place.

  The drive module 105 including the planetary gear speed reduction mechanism 110 according to the present embodiment supports the drive motor shaft 141 and the drum drive shaft 151 with a robust rigid bracket 130 as described above, and forms a part of the fixed internal gear 111. It is provided in the part that is flexibly deformed. With this configuration, it is possible to absorb fluctuations in the rotational speed of the drum drive shaft 151 due to eccentricity between the drum drive shaft 151 and the output shaft 119, and to perform highly accurate rotation transmission. Therefore, the drum drive shaft 151 and the drive module 105 are configured separately, and the coaxiality and straightness errors between the drum drive shaft 151 and the output shaft 119 can be absorbed. In addition, it is possible to provide a low-cost planetary gear reduction mechanism 110 that can suppress rotational speed fluctuations more than before and can transmit a rotational driving force with high accuracy.

(Example 2)
Example 2 which is a second example of the drive module 105 including the planetary gear speed reduction mechanism 110 according to this embodiment will be described. This embodiment is different from the first embodiment described above only in that a thin groove part is provided in a cylindrical portion of the fixed internal gear 111. Since other configurations and operations are the same, similar configurations and operations will be omitted as appropriate.

  In the drive module 105 including the planetary gear speed reduction mechanism 110 according to the present embodiment, as shown in FIG. 4, a portion on the outer peripheral side of the cylindrical portion of the fixed internal gear 111 is not provided with the gear portion 112. That is, a thin-walled groove portion 161 is provided at a portion other than the gear portion 112 on the outer peripheral side of the cylindrical portion of the fixed internal gear 111. More specifically, the groove portion 161 is provided in the vicinity of the motor-side end plate 135 where the gear portion 112 is not provided on the outer peripheral side of the cylindrical portion of the fixed internal gear 111. By providing in this way, when the planetary gear rotates eccentrically during the meshing rotation of the planetary gear, the fixed internal gear 111 can be arbitrarily deformed in the circumferential direction by the groove portion 161 to absorb the resistance force. . Since it can absorb in this way, it becomes possible to follow the eccentric rotation of the planetary gear as compared with the configuration of the first embodiment.

  The reason why the thin-walled groove portion 161 is arranged at a position other than the gear portion 112 of the fixed internal gear 111 is as follows. In general, the fixed internal gear 111 is made as a molded product using an engineering plastic material such as POM. However, if the gear portion 112 is present and a groove portion is formed at the opposite portion in the thickness direction to provide an uneven thickness portion, the tooth profile is deformed due to the sink phenomenon during cooling of the resin, and the accuracy is deteriorated. This is because proper meshing operation cannot be performed.

  The shape of the groove 161 shown in FIG. 4 may be formed as shown in FIG. In FIG. 5A, a chamfer is added so that the bottom of the groove 161 is U-shaped to suppress the occurrence of cracks due to repeated deformation fatigue. Moreover, in FIG.5 (b), while comprising the groove part 161 by two grooves, it forms so that each bottom part may become circular arc shape.

  With this configuration, the external force due to the displacement when the drum drive shaft 151 and the output shaft 119 are engaged is absorbed by the previous displacement from the portion where the thickness of the fixed internal gear 111 is reduced. By being absorbed in this way, the rotational speed fluctuation caused by the coupling between the drum drive shaft 151 and the output shaft 119 is reduced. In addition, from the viewpoint of the resin molding accuracy of the fixed internal gear 111, since the sharply changing portion is provided in the portion that does not mesh with the planetary gear, the tooth profile accuracy of the gear portion 112 due to sinking may be deteriorated. In addition, highly accurate rotation transmission can be performed.

(Example 3)
Example 3 which is a third example of the drive module 105 including the planetary gear speed reduction mechanism 110 according to this embodiment will be described. This embodiment is different from the first and second embodiments described above only in that a thin continuous region is provided in the cylindrical portion of the fixed internal gear 111. Since other configurations and operations are the same, similar configurations and operations will be omitted as appropriate.

  In the drive module 105 including the planetary gear speed reduction mechanism 110 according to the present embodiment, as shown in FIG. 6, a thin portion 162 that is a thin region continuously on the outer peripheral side of the cylindrical portion of the fixed internal gear 111. Was established. Specifically, the output shaft side end plate 136 straddling the position where the gear portion 112 is provided from the vicinity of the motor side end plate 135 where the gear portion 112 is not provided on the outer peripheral side of the cylindrical portion of the fixed internal gear 111. A thin portion 162 continuous to the vicinity was provided. By providing the thin portion 162 in this way, when the planetary gear rotates eccentrically during the meshing rotation of the planetary gear, the fixed internal gear 111 is arbitrarily deformed in the circumferential direction while being slightly small by the thin portion 162. To absorb resistance. And like the structure of Example 2, it was made to follow the eccentric rotation of a planetary gear rather than the structure of Example 1. FIG.

  In the present embodiment, similarly to the second embodiment, the deformation effect (the gear portion of the fixed internal gear 111) of the planetary gear 117 provided on the second stage carrier 118, which is a carrier having an output shaft, at the meshing portion. 112).

  As described above, the thin-walled portion 162 uniformly thins the outer peripheral side of the cylindrical portion of the fixed internal gear 111 in the entire region having a front and rear margin from the position where the gear portion 112 meshing with the planetary gear is present. ing. For this reason, there is no sudden change in the thickness on the outer peripheral side of the position where the gear portion 112 is provided, and it is possible to prevent deterioration of the tooth profile accuracy due to sink marks during molding. Further, like the second embodiment, it is desirable to provide a structure that suppresses generation of cracks due to repeated deformation fatigue by imparting an arc-shaped chamfer to the thinned portion, that is, the bottom corner.

  With this configuration, as in the second embodiment, when the drum drive shaft 151 and the output shaft 119 are engaged, the external force due to the displacement is due to the displacement of the fixed internal gear 111 from the portion where the thickness is reduced. Absorbed. By being absorbed in this way, the rotational speed fluctuation caused by the coupling between the drum drive shaft 151 and the output shaft 119 is reduced. In addition, in the resin molding accuracy of the fixed internal gear 111, since the rapidly changing thickness portion is provided in the portion that does not mesh with the planetary gear, the tooth profile accuracy of the gear portion 112 due to sink marks is not deteriorated. Accurate rotation transmission can be performed.

Example 4
Example 4 that is a fourth example of the drive module 105 including the planetary gear speed reduction mechanism 110 according to the present embodiment will be described. In the present embodiment and the above-described Embodiments 2 and 3, in the planetary gear speed reduction mechanism 110 provided with a plurality of planetary gears, the groove portion 163 or the thin portion 164 provided in the cylindrical portion of the fixed internal gear 111 is provided. Only the point related to the part is different. Since other configurations and operations are the same, similar configurations and operations will be omitted as appropriate.

  Also in this embodiment, in the planetary gear speed reduction mechanism 110 having only one planetary gear, the position where the wall thickness is reduced in order to deform the fixed internal gear 111 in the case of the groove 161 is that of the fixed internal gear 111. Provided in the vicinity of the output shaft side end plate 136. Further, in the case of the thin portion 162, the thickness of the region having a front and rear margin from the position where the gear portion 112 exists is reduced. However, in the planetary gear reduction mechanism 110 having two or more planetary gears, the groove portion 163 and the thin portion 164 are formed so that the portion of the fixed internal gear 111 that meshes with the planetary gear provided on the carrier 118 having the output shaft 119 is deformed. It was decided to provide. With this configuration, in order to secure a high reduction ratio, even when the number of carrier stages on which the planetary gear is provided increases and becomes multistage, it occurs at the meshing portion with the planetary gear provided on the last stage carrier. Fluctuation was absorbed by deformation action.

  Specifically, the configuration in which the groove portion 163 is provided is configured as follows. As shown in FIG. 7, the planetary gear 117 provided on the second-stage carrier 118, which is the final stage carrier, and the planetary gear 114 provided on the first-stage carrier 115, one stage before, are fixed internal teeth. The gear portion meshing with the gear 111 was divided into two. Then, it is deformed to the outer peripheral side of the fixed internal gear 111 at a position not engaged with any meshing portion of any planetary gear, at an intermediate point between the gear portion 112a meshing with the planetary gear 117 and the gear portion 112b meshing with the planetary gear 114. For this purpose, a groove 163 is provided. Here, with regard to the division of the gear portion 112a and the gear portion 112b, in the case of molding, a continuous tooth shape is formed from the relationship of the mold slide, and then a slit is provided in the middle of the secondary processing for division.

  In addition, the groove 163 provided on the outer peripheral side of the fixed internal gear 111 is similar to the groove 161 of the second embodiment in that the bottom of the groove 163 is chamfered so as to be cracked due to repeated deformation fatigue. It is desirable to have a structure that suppresses the occurrence of this. Further, as shown in FIG. 8 (a), it may be formed by two grooves, and each bottom may be formed in an arc shape.

  Moreover, in the structure which provides the thin part 164, it comprised as follows. Similar to the configuration in which the groove portion 163 is provided, the gear portion that meshes with the fixed internal gear 111 is divided into a gear portion 112 a that meshes with the planetary gear 117 at the final stage and a gear portion 112 b that meshes with the planetary gear 114. As shown in FIG. 8 (b), the outer periphery of the fixed internal gear 111 is slightly wider than the region where the gear portion 112a of the fixed internal gear 111 is provided and does not engage the region where the gear portion 112b is provided. On the side, a thin portion 164 for deformation is provided. Here, with respect to the division of the gear portion 112a and the gear portion 112b, in the case of molding, in the case of molding processing, after forming a continuous tooth shape from the relationship of the mold slide, secondary processing is performed. Split with a slit in the middle.

  In addition, regarding the shape of the thin portion 164 provided on the outer peripheral side of the fixed internal gear 111, similarly to the thin portion 162 of the third embodiment, an arc chamfer is added to the bottom corner, and cracks due to repeated deformation fatigue are provided. It is desirable to have a structure that suppresses the occurrence of

  In this way, even when the number of carrier stages increases to increase the number of carrier stages in order to ensure a high reduction ratio, the deformation that occurs at the meshing portion with the planetary gear provided on the last stage carrier is absorbed by the deformation operation. I can do it. It is the final stage of the planetary gear speed reduction mechanism 110 that is coupled to the drum drive shaft 151 to be driven, and this final stage also has a large deformation action due to torque fluctuation. As described above, by providing the fixed internal gear 111 with the groove portion 163 and the thin wall portion 164, it is possible to absorb the deformation at the meshing portion between the planetary gear at the final stage and the fixed internal gear 111, and to achieve high accuracy. Rotational transmission can be performed.

(Example 5)
Example 5 which is a fifth example of the drive module 105 including the planetary gear speed reduction mechanism 110 according to this embodiment will be described. The present embodiment differs from the second to fourth embodiments described above only in that a vibration absorbing material is applied to the outer peripheral side of the portion whose thickness is reduced in order to deform the fixed internal gear 111. Since other configurations and operations are the same, similar configurations and operations will be omitted as appropriate.

  In the present embodiment, as shown in FIG. 9, the vibration absorbing material is applied to the configuration described in the third embodiment, that is, the configuration in which a thin continuous region is provided in the cylindrical portion of the fixed internal gear 111. The case where it does is demonstrated.

  Although the fluctuation component of one rotation period of the output shaft 119 is eliminated by deformation at the portion where the thin-walled portion 162 of the fixed internal gear 111 is provided, the vibration in the high frequency band and its n-th order are caused by the movement of the resonance frequency. There is a possibility of increasing the frequency. Therefore, in this embodiment, as shown in FIG. 9, the vibration-absorbing material composed of elastic and deformable elastomer is thin-walled so as to be symmetrical with respect to the central axis of the fixed internal gear 111. This is applied to the outer periphery of the fixed internal gear 111 provided with the portion 162. By applying in this way, the elastomer portion 165 having a uniform thickness is formed in the portion where the thin portion 162 of the fixed internal gear 111 is provided, and the viscosity and mass of the portion where the thin portion 162 is provided are increased. The vibration was attenuated.

  Specifically, an elastomer portion 165 composed of an elastomer such as urethane rubber, chloroprene rubber, nitrile rubber, or SBR rubber molded with a thickness of several millimeters is brought into close contact with a portion of the fixed internal gear 111 that is deformed. Cover and fix. That is, it covers and fixes so that it may contact | adhere to the thin part 162 provided in the fixed internal gear 111. Since the elastomer portion 165 configured as described above has viscosity, vibration of a minute twist deformation component can be converted into heat inside and dissipated, and the vibration in the high frequency band as described above is slight. Etc. can be attenuated. Each time the carrier 118 provided with the last stage planetary gear 117 rotates, the elastomer portion 165 follows while deforming, and due to its viscosity and mass effect, the resonance frequency band moves with respect to rotation and lateral vibration. And the vibration amplitude attenuation effect is demonstrated. Therefore, it is possible to transmit rotation with higher accuracy than the configuration in which the groove 161 and the thin portion 162 are provided.

(Example 6)
Example 6 which is a sixth example of the drive module 105 including the planetary gear speed reduction mechanism 110 according to this embodiment will be described. The present embodiment is different from the above-described embodiment 5 only in that the method for fixing the vibration absorbing material to be applied to the outer peripheral side of the portion where the thickness of the fixed internal gear 111 is reduced is defined. Since other configurations and operations are the same, similar configurations and operations will be omitted as appropriate.

  Similarly to the fifth embodiment, the present embodiment also applies the vibration-absorbing material to the configuration described in the third embodiment, that is, the configuration in which the continuous thin portion is provided in the cylindrical portion of the fixed internal gear 111. The case will be described.

  As shown in FIG. 9, the elastomer portion 165, which is a vibration absorbing material, and the fixed internal gear 111 are fixed by fitting. Further, the inner diameter of the elastomer portion 165 to be fitted is set to be slightly smaller than the outer diameter of the thin portion 162 of the fixed internal gear 111 to which the elastomer portion 165 is fitted, so that the two are in close contact with each other at the time of mounting. It is a fitting tolerance. Then, the elastomer portion 165 is fixed so that at least the thin portion 162 for deformation provided in the fixed internal gear 111 is buried.

  In this way, the elastomer portion 165, which is the vibration absorbing material to be applied, is securely brought into close contact with the fixed internal gear 111 to attenuate the amplitude of the generated vibration. At the same time, it is possible to prevent the elastomer portion 165 that is a vibration absorbing material from falling off.

  Also, in forming the fixing position of the elastomer portion 165, which is a vibration absorbing material, to the fixed internal gear 111, it is necessary to consider so that sink marks during molding do not deteriorate the accuracy of the gear portion 112, which is an internal gear. . For this reason, in this embodiment, a configuration is adopted in which an uneven shape is not provided in the vicinity of the tooth profile of the portion meshing with each planetary gear. In order to further integrate the elastomer portion 165 and the fixed internal gear 111, an adhesive 166 is interposed between the two to enhance the bonding force.

  As the adhesive 166, a cyanoacrylic instant adhesive such as Cemedine 3000 (trade name) or a rubber solvent type adhesive such as Cemedine 575 (trade name) can be used. However, since the outer periphery of the molded fixed internal gear 111 is a smooth surface, fine irregularities are formed by sandblasting or melting by laser after molding. By interposing an adhesive in the gap formed in this way, an anchor effect (entanglement effect) can be secured in addition to the adhesion effect, and robust fixing becomes possible.

As described above, the planetary gear speed reduction mechanism 110 of the present embodiment can provide the following operational effects. Since the output shaft 119 that transmits the rotational driving force to the drum drive shaft 151 has an internal gear that meshes with the external gear 153 formed at the tip of the drum drive shaft 151, the drum drive shaft 151 and the output shaft 119 are provided. It can be configured separately and separated. Since separation is possible in this way, maintenance can be improved as compared with a method in which a rotating shaft and a drive system of a rotating body are first integrated and assembled into a device main body to be used. Further, by floatingly supporting the second-stage carrier 118 having the output shaft 119, it is possible to allow more errors in coaxiality and straightness than in the case of supporting by a bearing, and to perform rotation with a degree of freedom. be able to. Since rotation can be performed in this way, high-accuracy rotation is possible in which fluctuations in the rotation speed of the drum drive shaft 151 are suppressed as compared with the case where the drum drive shaft 151 is supported by a bearing. Further, by floatingly supporting the second-stage carrier 118 having the output shaft 119, the accuracy and assembly accuracy of each part with an increase in manufacturing cost, such as the planetary reduction mechanism described in Patent Document 2, is increased. Therefore, fluctuations in rotational speed can be suppressed, and an increase in manufacturing cost can be suppressed. In addition, the rigid bracket 130 to which the planetary gear reduction mechanism 110 and the drive motor 140 are attached ensures the coaxiality of the drum drive shaft 151 and the drive motor shaft 141, and the output shaft 119 side of the resin-made fixed internal gear 111. Does not regulate or fix the positioning. Since the resin-made fixed internal gear 111 is fixed in this way, a part of the fixed internal gear 111 is deformed by a force generated by an eccentric error between the drum drive shaft 151 and the output shaft 119 during rotational driving. With this deformation, it is possible to reduce fluctuations in rotational torque caused by the coupling between the drum drive shaft 151 and the output shaft 119 during rotational drive. Further, the deformation amount of this deformation is added to the amount such as the coaxiality or straightness error between the drum drive shaft 151 and the output shaft 119, which can be allowed only by floatingly supporting the carrier 118 having the output shaft 119. be able to. As a result, it is possible to tolerate more than the configuration in which the second-stage carrier 118 having the output shaft 119 is supported by floating. Therefore, it is possible to absorb more fluctuations in the rotational speed of the drum drive shaft 151 than in a configuration in which the second-stage carrier 118 having the output shaft 119 is only supported in a floating manner. Therefore, it absorbs errors in the coaxiality and straightness between the drum drive shaft 151 and the output shaft 119, suppresses rotational speed fluctuations compared to the prior art, and can transmit rotational drive force with high accuracy and low cost. A planetary gear reduction mechanism 110 can be provided.
Further, the planetary gear reduction mechanism 110 of the present embodiment can provide the following operational effects. A groove portion 161 is provided in the vicinity of the motor-side end plate 135 where the gear portion 112 is not provided on the outer peripheral side of the cylindrical portion of the fixed internal gear 111 and on the outer peripheral side of the cylindrical portion of the fixed internal gear 111. By providing the groove portion 161 in this way, when the planetary gear is eccentrically rotated during the meshing rotation of the planetary gear, the fixed internal gear 111 is arbitrarily deformed in the circumferential direction in the groove portion 161 but is arbitrarily deformed. Can be absorbed. By absorbing in this way, it is possible to follow the eccentric rotation of the planetary gear as compared with the configuration in which the groove portion 161 is not provided. Further, since the groove portion 161 which is a portion where the wall thickness changes suddenly is arranged at a position other than the gear portion 112 which meshes with the planetary gear, a sink phenomenon occurs in the gear portion 112 when the fixed internal gear 111 is formed. The tooth profile accuracy can be prevented from deteriorating. Therefore, the rotational speed fluctuation of the drum drive shaft 151 is further reduced as compared with the configuration in which the groove portion 161 is not provided, and high-precision rotation transmission is performed without deteriorating the tooth profile accuracy of the gear portion 112 due to sink marks. Can do.
Further, the planetary gear reduction mechanism 110 of the present embodiment can provide the following operational effects. Continuous from the vicinity of the motor side end plate 135 where the gear portion 112 is not provided on the outer peripheral side of the cylindrical portion of the fixed internal gear 111 to the vicinity of the output shaft side end plate 136 across the position where the gear portion 112 is provided. The thin wall portion 162 was provided. By providing the thin wall portion 162 in this manner, when the planetary gear is eccentrically rotated during the meshing rotation of the planetary gear, the fixed internal gear 111 is arbitrarily deformed in the circumferential direction by the groove portion 161 and resists. Can absorb power. By absorbing in this way, it is possible to follow the eccentric rotation of the planetary gear as compared with the configuration in which the thin portion 162 is not provided. Further, the thin wall portion 162 is provided in a region having a front and rear margin from the position where the gear portion 112 that meshes with the planetary gear is present, and a sudden change in the wall thickness on the outer peripheral side of the position where the gear portion 112 is provided. No, it is possible to prevent the deterioration of the tooth profile accuracy due to sink marks during molding. Therefore, the rotational speed fluctuation of the drum drive shaft 151 is further reduced as compared with the configuration in which the thin portion 162 is not provided, and highly accurate rotation transmission is performed without degrading the tooth profile accuracy of the gear portion 112 due to sink marks. be able to.
Further, the planetary gear reduction mechanism 110 of the present embodiment can provide the following operational effects. The gear portion in which the planetary gear 117 in the final stage and the planetary gear 114 in the previous stage are meshed with the fixed internal gear 111 is divided into the gear part 112a in which the planetary gear 117 meshes and the gear part 112b in which the planetary gear 114 meshes. And the groove part 163 and the thin part 164 are provided with respect to the gear part 112a. Specifically, when the groove portion 163 is provided, on the outer peripheral side of the fixed internal gear 111 at a position that is intermediate between the divided gear portion 112a and the gear portion 112b and does not engage with the meshing portion of any planetary gear, A groove 163 is provided for deformation. Further, when the thin portion 164 is provided, it is slightly wider than the region where the gear portion 112a is provided, and is deformed to the outer peripheral side of the fixed internal gear 111 at a position which does not engage with the region where the gear portion 112b is provided. A thin portion 164 is provided. By providing the groove portion 163 and the thin wall portion 164 on the outer peripheral side of the fixed internal gear 111 in this way, fluctuations that occur at the meshing portion with the planetary gear 117 provided on the carrier 118 at the final stage are reduced. It can be absorbed by the deformation operation of 164. In addition, the groove portion 163 and the thin portion 164 where a sudden change in thickness occurs is provided on the outer peripheral side other than the position where the gear portions 112a and 112b meshing with the planetary gear exist, and the tooth profile accuracy due to sink marks at the time of molding Can be prevented. Therefore, the rotational speed fluctuation of the drum drive shaft 151 is reduced as compared with the configuration in which the groove portion 161 and the thin portion 162 are not provided, and the tooth profile accuracy of the gear portions 112a and 112b due to sink marks is not deteriorated, and high-precision rotation is achieved. Can communicate.
Further, the planetary gear reduction mechanism 110 of the present embodiment can provide the following operational effects. The portion of the fixed internal gear 111 whose shape is to be deformed, that is, the portion provided with the thin portion 162 is covered and fixed so as to be in close contact with an elastomer portion 165 made of a deformable elastomer. By fixing in this way, since the elastomer part 165 has viscosity, vibrations of a minute torsional deformation component can be converted to heat inside and dissipated, and a slight amount of vibration in the high frequency band, etc. The amplitude can be attenuated. Then, for each rotation of the carrier 118 provided with the planetary gear 117 at the final stage, the elastomer portion 165 follows while deforming, and due to its viscosity and mass effect, the resonance frequency band is moved with respect to rotation and lateral vibration. Demonstrates the effect of damping vibration amplitude. Therefore, the configuration in which the groove portion 161 and the thin portion 162 are simply provided by exhibiting the rotational frequency fluctuation of the drum drive shaft 151 by moving the resonance frequency band and attenuating the vibration amplitude with respect to rotation and lateral vibration. Therefore, it is possible to perform rotation transmission with higher accuracy.
Further, the planetary gear reduction mechanism 110 of the present embodiment can provide the following operational effects. The inner diameter of the elastomer part 165 to be fitted is set to be slightly smaller than the outer diameter of the thin-walled part 162 of the fixed internal gear 111 to which the elastomer part 165 is fitted. Tolerance. Then, the elastomer portion 165 is fixed so that at least the thin portion 162 for deformation provided in the fixed internal gear 111 is buried. By fixing in this way, the elastomer portion 165 which is a vibration absorbing material applied to the fixed internal gear 111 is securely brought into close contact with the fixed internal gear 111 to attenuate the amplitude of the generated vibration, and at the same time, Dropping can be prevented.
Further, in the planetary gear reduction mechanism 110 of the present embodiment, the floating support of the second stage carrier 118 having the output shaft 119 is carried out by the plurality of planetary gears 114 provided on the carrier 118 and the gear portion 112 of the fixed internal gear 111. It is done by meshing with. By thus supporting the carrier 118 in a floating manner, it is not necessary to provide a ball bearing or the like, and an increase in the manufacturing cost of the planetary gear reduction mechanism 110 can be suppressed, and the planetary gear reduction mechanism 110 can be downsized.
In addition, the drive module 105 that is the rotation drive device of the present embodiment includes any one of the planetary gear reduction mechanisms 110 described above as a mechanism that reduces and transmits the rotational drive force of the drive motor 140 to the photosensitive drum 40. Therefore, the same operational effects as any of the planetary gear reduction mechanisms 110 described above can be achieved.
Further, in the multi-function machine that is the image forming apparatus of the present embodiment, at least one of the planetary gear reduction mechanisms 110 described above or the above-described drive module is used to rotate at least the photosensitive drum 40 among a plurality of rotating bodies provided. 105. Therefore, the same operational effects as any of the planetary gear reduction mechanism 110 described above or the drive module 105 described above can be achieved.

40 Photosensitive drum 105 Driving module 110 Planetary gear reduction mechanism 111 Fixed internal gear 112 Gear portion 113 First stage sun gear 114 First stage planetary gear 115 First stage carrier 116 Second stage sun gear 117 Second stage Eye planetary gear 118 Second stage carrier 119 Output shaft 120 Bracket positioning hole 130 Rigid bracket 131 Base portion 132 Convex positioning portion 133 Motor holder 134 Motor plate 135 Motor side end plate 136 Output shaft side end plate 140 Drive motor 141 Drive Motor shaft 150 Photosensitive drum unit 151 Drum drive shaft 153 External gear 154 Drum holder 155 Ball bearing 160 Side plate 161, 163 Groove 162, 164 Thin part 165 Elastomer part 166 Adhesive

JP 2009-037198 A Japanese Patent No. 4360162

Claims (9)

An output shaft having a joint portion for transmitting a rotational driving force to a drive shaft of a rotated body, a fixed internal gear, a plurality of planetary gears meshed with the fixed internal gear, and a carrier having the output shaft. In the planetary gear mechanism mounted on the apparatus main body provided with the rotated body in combination with the rotation drive source,
The planetary gear mechanism and the rotational drive source are attached and fixed to the side plate of the apparatus body via a rigid bracket,
The bracket ensures the coaxiality of the drive shaft of the driven body and the drive shaft of the rotary drive source,
The carrier having the output shaft is supported floating,
The fixed internal gear is a resin molded product,
The output shaft side of the fixed internal gear is neither positioned nor fixed,
A planetary gear mechanism characterized in that a part of the fixed internal gear is deformed by a force generated by an eccentric error between a drive shaft and an output shaft of a driven body during rotational driving. The planetary gear mechanism according to claim 1,
A planetary gear mechanism characterized in that, in order to obtain the deformability of a fixed internal gear, a thin groove portion is formed in a portion of the fixed internal gear in a portion where the planetary gear does not mesh. The planetary gear mechanism according to claim 1,
A planetary gear mechanism characterized in that a continuous thin portion is formed in a part of the fixed internal gear in order to obtain the deformability of the fixed internal gear. The planetary gear mechanism according to claim 2 or 3,
A planetary gear mechanism characterized in that a groove or a thin part is provided in the vicinity of a planetary gear of a carrier having an output shaft in order to obtain the deformability of a fixed internal gear that is equal to or higher than the two-speed transmission mechanism. The planetary gear mechanism according to any one of claims 2 to 4,
A planetary gear mechanism, characterized in that an elastic vibration-absorbing material composed of a deformable elastomer is applied to the outer periphery of the fixed internal gear provided with a groove or thin portion. The planetary gear mechanism according to claim 5,
A planetary gear mechanism characterized in that the vibration-absorbing material is fixed so as to be buried in at least the thin portion for deformation provided in the fixed internal gear. The planetary gear mechanism according to any one of claims 1 to 6,
The floating support of the carrier with the output shaft is
A planetary gear mechanism, wherein the planetary gear mechanism is formed by meshing a plurality of planetary gears and fixed internal gears included in the carrier. In the rotational drive device that rotationally drives the rotating object,
A rotary drive device comprising the planetary gear mechanism according to any one of claims 1 to 7 as a mechanism for shifting and transmitting a rotational drive force of a rotational drive source to a rotated body. In an image forming apparatus having a plurality of rotating bodies,
The planetary gear mechanism according to any one of claims 1 to 7 or the rotary drive device according to claim 8 is used for rotational driving of at least one of the plurality of rotating bodies. An image forming apparatus.

Images